Ok, so I just was thinking...I'm looking at getting a 100 2.8 macro (canon) for portrait and product photography for my business (graphic design). Now first and foremost I love more fine art photography but I do in-house photography at the studio for the money. I was wondering: 1. Is there a comparable lens made by a 3rd party manufacturer? 2. Is it worth the price difference? 3. Are there any canon users here who use 3rd party lenses at a comparable focal length for portraits/product shots?